Method and apparatus for forming integral coupling flanges in hollow metallic articles

ABSTRACT

A method and apparatus for forming integral coupling flanges about surface openings in hollow metallic articles. The region of the metallic article about the opening is continuously heated by means of gas burners throughout formation of the flange at a temperature which is suitable for the shaping of the metal of the article. An extruding tool, having a surface layer fabricated of material having a low thermal conduction characteristic, is moved through the surface opening of the metallic article during this heating to form the flange. The gas burners are adapted for heating both the peripheral surface of the article about the opening therein and the flange as it is formed, and the extruding tool may include an intermediate support means which supports and thermally insulates the surface layer of the extruding tool on an inner support element thereof.

United States Patent 1191 1111 3,910,094 Liittgert et al. Oct. 7, 1975 [54] METHOD AND APPARATUS FOR FORMING 2,861,335 11/1958 Huet 72 342 INTEGRAL COUPLING FLANGES IN HOLLOW METALLIC ARTICLES Primary Examiner-Lowell A. Larson [75] Inventors: Hans Limgert; Karl Brunk; Attorney, Agent, or Firm-Kenyon & Kenyon Reilly Johannes Dietrich; Emanuel Pahl, & Chapm all of Berlin, Germany [73] Assignee: Siemens Aktiengesellschaft, Munich, [57] ABSTRACT Germany A method and apparatus for forming integral coupling 22 Filed; Apt 5 974 flanges about surface openings in hollow metallic articles. The region of the metallic article about the open [211 App]' 458,409 ing is continuously heated by means of gas burners throughout formation of the flange at a temperature 30 Foreign Application priority Data which is suitable for the shaping of the metal of the Apr 6 I973 Germany 2318064 article. An extruding tool, having a surface layer fabri- Apr'61973 Germany 2318060 cated of material having a low thermal conduction characteristic, is moved through the surface opening 52 us. 01. 72 342- 29 157 T the metallic article during/this heating form the Int B2lD/51/40 flange. The gas burners are adapted for heating both [5 ie d f 69 7O 71 he peripheral surface of the article about the opening 72/1 5 5 1 therein and the flange as it is formed, and the extruding tool may include an intermediate support means [56] References Cited which supports and thermally insulates the surface layer of the extruding tool on an inner support ele- UNITED STATES PATENTS mem thereofi 354,879 12/1886 Youngs 72/342 1,574,900 3/ 1926 Kellogg 72/342 16 Claims, 7 Drawing Figures Sheet 1 of 2 US. Patent 0a. 7,1975

US. Patent Oct. 7,1975 Sheet 2 of 2 3,910,094

METHOD AND APPARATUS FOR FORMING INTEGRAL COUPLING FLANGES IN HOLLOW METALLIC ARTICLES BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to an improved method and apparatus for forming integral coupling flanges in hollow, metallic articles.

2. Description of the Prior Art It is known in the prior art to form coupling flanges and the like in hollow metallic articles, such as tubes and containers, by heating the area thereof about a surface opening provided therein to soften the metal of the article, and then moving an extruding tool by means of a suitable transport device outwardly through the opening from the interior space of the hollow article. The tool bends the edges of the article opening outwardly to form a collar or flange which can be welded or otherwise coupled to pipes, conduits and the like.

As stated above, it is necessary to heat the region about the metallic article opening in order to soften the article metal and enable shaping of the flange with the extruding tool. Prior art methods and apparatus which have been used to form flanges on thin-walled hollow articles have not generally been able to maintain the temperature of the article region about the opening at a level suitable for shaping throughout the entire flange forming operation. Thus, a large amount of energy is expended in shaping the flange by means of such methods and apparatus.

SUMMARY OF THE INVENTION It is therefore an object of the invention to overcome the aforementioned disadvantages of heretofore known methods and apparatus, and to provide an improved method and apparatus for forming integral coupling flanges about surface openings in hollow metallic articles.

These and other objects are achieved by the present invention in a method of forming an integral coupling flange about a surface opening in a hollow metallic article, in which the article is heated in the region of the opening to a temperature which is suitable for the shaping of the metal thereof, and an integral coupling flange is formed by moving an extruding tool outwardly through the opening from the interior space of the hollow article. The improvement of the inventive method comprises the steps of continuously heating the metallic article about the surface opening thereof at the temperature suitable for shaping of the metal thereof throughout the shaping of the metal and formation of the flange, and shaping the metal by moving an extruding tool having a low thermal conduction characteristic through the opening. The step of continuously heating the region about the surface opening preferably includes the heating of the region of the opening prior to moving the extruding tool therethrough, and further, heating the flange formed by the tool as the tool is moved through the article opening.

The above objects are also achieved by the invention in an apparatus for forming an integral flange in such an article which comprises gas burner means adapted so to be movable to the region of the article opening for heating the region thereabout at a temperature suitable for the shaping of the metal thereof, and an extruding tool which is movable through the article opening outwardly from the interior thereof for shaping the metal of the article and forming the flange, and includes a surface layer which engages the article metal and is formed of material having a low thermal conduction characteristic. The gas burner means preferably comprises a first curved gas burner having downwardly directed nozzles which heat the region of the article about the opening thereof prior to formation of the flange, and a second curved gas burner having outwardly directed nozzles which heat the flange formed by the tool as it is moved through the article opening. The extruding tool may include an inner support element, a surface layer disposed thereon fabricated of non-scaling sheet metal having a low thermal conduction characteristic, and an intermediate support means, which may comprise a plurality of support members such as wires, or thermal insulation material, interposed between the support element and surface layer for supporting and thermally insulating the surface layer on the inner support element. Alternatively the extruding tool may comprise the inner support element and an outer surface layer of ceramic material, or an inner support element having surface grooves which diminish the support area for the surface layer. The tool is preferably conical in :shape, and has an upper portion which is shaped to correspond to the shape of the article opening, and a lower portion which is shaped to correspond to that of the flange to be formed.

In prior art methods, the metallic article is generally preheated in a heating apparatus before utilization of the extruding tool and formation of the flange. In contrast, the present invention provides that the article be continuously heated by gas burner means which are adapted to adjust to the shape of the article about the surface opening thereof, so that the article is heated also during formation of the flange to compensate for heat losses in the article and through the extruding tool, which cannot be ideally thermally insulated. With the method and apparatus of the invention, the time required to carry out the flange forming process is reduced; the quality of the article flange formed is increased; the structure of the metal of the article is not damaged; and the previously required, time consuming annealing process is eliminated.

These and other features of the invention disclosed and claimed herein will be discussed in detail in the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a hollow, metallic article and part of the improved flange forming apparatus constructed according to the invention, prior to formation of the article flange;

FIG. 2 is an exploded perspective view of the article and the flange forming apparatus of the invention, subsequent to the formation of the article flange;

FIG. 3 is a perspective view of alternative embodiments of an extruding tool inner support element constructed according to the invention;

FIG. 4 is a side view, partly in cross-section, of another embodiment of an extruding tool constructed according to the invention;

FIG. 5 is a side view, partly in cross-section, of still another embodiment of an extruding tool constructed according to the invention;

FIG. 6 is a top view of still a further embodiment of an extruding tool constructed according to the invention; and

FIG. 7 is a side view of the tool illustrated in FIG. 6.

DETAILED DESCRIPTION Referring now to the drawings, in particular to FIGS. 1 and 2, there is shown a hollow, metallic article, illustrated as cylinder 1 having radial end flanges 2, in which an elliptical shaped surface opening 3, about which the flange is formed, is disposed. Gas burner means, illustrated as curved gas burners 4, are disposed about the opening and are movable to and from the region thereof. The burner means heats the metal of the article about the surface opening to a temperature which renders it soft enough to be shaped. Gas burners 4 are preferably semi-elliptical in shape and include downwardly directed nozzles for directing the gas flames thereof towards the surface of cylinder 1 about opening 3. Supply pipes transport a bumable gas mixture to the burners and function as a handle for moving the burners to and from the region of opening 3. The dimensions of the gas burners 4 are preferably such that approximately one half of the peripheral area on each side of opening 3 is covered by each burner. It should also be noted that opening 3 has not been illustrated in FIG. 1 in its original elliptical shape, but rather is shown partly reshaped as a result of the heating of the cylinder by the gas burners.

The extruding tool of the invention is shown in FIG. 2, and comprises an inner support element, generally designated 13, a surface layer fabricated of nonscaling sheet metal having a low thermal conduction characteristic disposed on element 13, and intermediate support means 14, illustrated in FIG. 2 as a plurality of circular wires interconnected in a basket configuration, interposed between element 13 and surface layer 15 for supporting and thermally insulating the surface layer on support element 13. The dimensions of the inner support element 13, surface layer 15, and the wire basket are matched so that linear contact between wires 18, element 13 and surface layer 15 is assured. The air spaces between the wires of the basket thermally insulate element 13 from surface layer 15 and inhibit the flow of heat from layer 15 to the inner support element, thereby reducing heat loss during formation of the flange. The main body portion 16 of element 13 is conical in shape and wires 18 are preferably arranged thereon so as to extend along the lines thereof of steepest gradient.

Element 13 further includes a flange forming portion 17 at the lower end thereof which, in the illustrated embodiment of the invention, is cylindrical in shape. The upper end thereof includes a coupling member 12 which is connected to a suitable device, such as a hydraulic puller, which moves the extruding tool through opening 3 outwardly from the interior space of cylinder 1, for forming the flange 7 thereabout. Since such devices are known in the art, they are not described in detail herein.

Second curved gas burners 11, only one of which is illustrated in FIG. 2, are provided for heating the flange 7 as it is formed by the extruding tool. Burner 10 includes a gas mixture supply pipe 11 which functions in the same manner as supply pipes 5 of burners 4, and is cylindrical in shape to correspond to that of the flange. Burner 10 includes nozzles which are outwardly directed towards flange 7 for heating the latter continuously during formation thereof at a temperature which renders the metal of cylinder 1 suitably soft for shaping. It should be noted that burners 10 are shaped differently from burners 4 since opening 3 is shaped in the form of a bulging ellipse and the flange to be formed is circular in shape. The direction of the nozzles, and their disposition with respect to the center of opening 3, must be varied to ensure proper heating of the article.

The burners may be rendered movable with respect to the article opening by mounting them on displaceable, pivotable slides which are movable by means of automatic or manual controls. The supply of the burnable gas mixture to the burners is regulated as necessary by a manual control, and preferably with the use of temperature sensors so that a suitable temperature range of the metal of the article is maintained.

Instead of the wire basket illustrated in FIG. 2, the intermediate support means may comprise merely a plurality of support members, for example, a plurality of circular wires, disposed on support element 13, along the steepest gradient lines of portion 16 thereof. Even if a large number of such support elements are used, the total area of the surface layer is much greater than the area of the surface layer which engages the support elements, and heat transfer between element 13 and surface layer 15 is effectively inhibited.

FIGS. 3-7 illustrate alternative embodiments of the extruding tool of the apparatus. In FIG. 3, inner support element 13 is provided with a plurality of spaced apart surface grooves which form a support surface for surface layer 15. Those portions of element 13 between the grooves engage surface layer 15 when it is disposed thereon and provide a support surface which is diminished in area with respect to the total surface area of element 13. Heat transfer between the inner support element and surface layer is thereby effectively inhibited. The surface grooves may be longitudinal grooves 21 which extend axially along the lines of steepest gradient of element 13, or, alternatively, circumferential grooves 22 which extend around element 13. Moreover, both types of grooves may be utilized on the same support element to provide the required support surface, if desired.

As illustrated in FIG. 4, the intermediate support means may comprise a layer of thermal insulation material 23, such as, for example, mineral wool, or a combination of mineral and organic materials. The mass of material fills the space between the element 13 and surface layer 15 and thereby inhibits heat transfer between the two. The separate surface layer shell and intermediate support means may also be dispensed with and a unitary extruding tool constructed by coating the surface of element 13 with a surface layer of ceramic material 25, as shown in FIG. 5. Because the layer of ceramic material is thin it stores littleheat.

The extruding tools illustrated in and described with reference to FIGS. 2-5 include an inner support element which is conical in shape. As aresult, it happens that theupper portion of the tool which is first moved through article opening 3 when forming flange 7 engages cylinder 1 about opening 3 only at separate points. The upper portion 27 of the extruding tool 6 illustrated in FIGS. 6 and 7, however, is elliptical in shape, corresponding to that of opening 3, so that the upper portion of the extruding tool engages the entire periphery of opening 3 as it is moved therethrough. This assures that the metal of the article is uniformly stressed during formation of the flange. The lower portion 28 of the tool is, of course, cylindrical in shape as previously described. It is also preferable if the tool is shaped so that its surface 30 is in the form of a tractrix curve. This results in a particularly favorable application of the applied forces produced by the tool.

Although burners 4 and have been illustrated as being the segment type, it should be noted that other type burners may be utilized, such as burners with adjustable nozzles which can direct the gas flames thereof both downwardly and outwardly. Also, different size segment burners, covering other than half of the periphery about the article opening or flange, may also be utilized. Movement of the burners may be attained by guide tubes, rollers, or the like, either manually, or automatically with respect to metal temperature and position of the extruding tool.

In the method of the invention, burners 4 are first moved to the position illustrated in FIG. 1 about opening 3 and heat the region there to a temperature sufficient to soften the metal of cylinder 2 and thereby render it suitable for shaping. The extruding tool 6 is then moved from the interior space of cylinder 2 outwardly through opening 3. As soon as the edge of opening 3 begins to bulge outwardly, burners 4 are retracted and are replaced by burners 10 which continue to heat the flange 7 being formed as the extruding tool continues to move at the temperature suited for shaping of the cylinder metal. By means of this continuous heating of the cylinder about opening 3, the temperature of the metal is maintained relatively constant during the entire shaping process. When the extruding tool has been moved completely through opening 3, burners 10 are removed and flange 7 is permitted to cool. A subsequent annealing of the flange after formation is not needed due to the fact that the metal of the article shaped is maintained at a temperature suitable for its shaping throughout formation of the flange.

In the foregoing specification, the invention has been described with reference to specific exemplary embodiments thereof. It will, however, be evident, that various modifications and changes may be made thereunto without departing from the broader spirit and scope of the invention as set forth in the appended claims. The

specification and drawings are, accordingly, to be regarded in an illustrative rather than in a restrictive sense.

What is claimed is:

1. In a method of forming an integral coupling flange in a hollow metallic article, said article, including a surface opening therein about which said flange is formed, in which said article is heated in the region of said opening to a temperature suitable for the shaping of the metal thereof, and said flange is formed by moving an extruding tool through said opening from the interior of said article the improvement comprising the steps of:

continuously heating the metallic article in the region of said opening at said temperature suitable for shaping of the metal thereof throughout the shaping of the metal and formation of the flange, and shaping said metal to form said flange by moving an extruding tool having a low thermal conduction characteristic through said opening whereby the flow of heat drawn from said metal by said tool is minimized thereby facilitating maintaining said temperature in said metal as the same is shaped.

2. The method recited in claim 1, wherein said step of continuously heating includes heating the region about the periphery of said opening prior to moving said extruding tool therethrough, and then heating the flange formed as said tool is moved through said opening.

3. Apparatus for forming an integral coupling flange in a hollow metallic article, said article including a surface opening therein about which said flange is formed, comprising:

gas burner means, adapted so as to be movable to the region of said opening, for heating the article in said region at a temperature suitable for the shaping of the metal thereof; and

an extruding tool, movable through said opening outwardly from the interior of said article, for shaping said metal to form said flange, said too] including an outer surface layer formed of material having a low thermal conduction characteristic.

4. The apparatus recited in claim 3, wherein said gas burner means comprises a first curved gas burner having downwardly directed nozzles for heating said region about said opening prior to formation of said flange, and a second curved gas burner having outwardly directed nozzles for heating the flange formed by said extruding tool as said tool is moved through said opening.

5. The apparatus recited in claim 3, wherein said extruding tool comprises an inner support element, a surface layer disposed thereon fabricated of non-scaling sheet metal having a low thermal conduction characteristic, and intermediate support means, interposed between said inner support element and surface layer, for supporting and thermally insulating said surface layer on said inner support element.

6. The apparatus recited in claim 5, wherein said intermediate support means comprises thermal insulation material.

7. The apparatus recited in claim 5, wherein said intermediate support means comprises a plurality of support members disposed on the surface of said inner support element.

8. The apparatus recited in claim 7, wherein said support members comprise a plurality of interconnected circular wires disposed on the surface of said inner support element.

9. The apparatus recited in claim 8, wherein said inner support element is conical in shape, and wherein said wires are disposed on the surface of said inner support element along the lines thereof of steepest gradient, and are interconnected so as to form a basket shaped intermediate support element.

10. The apparatus recited in claim 3, wherein said extruding tool comprises an inner support element and a surface layer disposed thereon fabricated of nonscaling sheet metal having a low thermal conduction characteristic, said inner support element having a plurality of surface grooves disposed therein for forming a support surface for said surface layer which is diminished in area with respect to the total surface area of said inner support element.

11. The apparatus recited in claim 10, wherein said inner support element is conical in shape and said grooves extend axially along the lines thereof of steepest gradient.

and a lower portion having a shape corresponding to that of the flange to be formed.

15. The apparatus recited in claim 14, wherein said upper portion and said opening are elliptical in shape, and wherein said lower portion and flange are circular in shape.

16. The apparatus recited in claim 15, wherein the surface shape of said extruding tool is in the form of a tractrix curve. 

1. In a method of forming an integral coupling flange in a hollow metallic article, said article, including a surface opening therein about which said flange is formed, in which said article is heated in the region of said opening to a temperature suitable for the shaping of the metal thereof, and said flange is formed by moving an extruding tool through said opening from the interior of said article the improvement comprising the steps of: continuously heating the metallic article in the region of said opening at said temperature suitable for shaping of the metal thereof throughout the shaping of the metal and formation of the flange, and shaping said metal to form said flange by moving an extruding tool having a low thermal conduction characteristic through said opening whereby the flow of heat drawn from said metal by said tool is minimized thereby facilitating maintaining said temperature in said metal as the same is shaped.
 2. The method recited in claim 1, wherein said step of continuously heating includes heating the region about the periphery of said opening prior to moving said extruding tool therethrough, and then heating the flange formed as said tool is moved through said opening.
 3. Apparatus for forming an integral coupling flange in a hollow metallic article, said article including a surface opening therein about which said flange is formed, comprising: gas burner means, adapted so as to be movable to the region of said opening, for heating the article in said region at a temperature suitable for the shaping of the metal thereof; and an extruding tool, movable through said opening outwardly from the interior of said article, for shaping said metal to form said flange, said tool including an outer surface layer formed of material having a low thermal conduction characteristic.
 4. The apparatus recited in claim 3, wherein said gas burner means comprises a first curved gas burner having downwardly directed nozzles for heating said region about said opening prior to formation of said flange, and a second curved gas burner having outwardly directed nozzles for heating the flange formed by said extruding tool as said tool is moved through said opening.
 5. The apparatus recited in claim 3, wherein said extruding tool comprises an inner support element, a surface layer disposed thereon fabricated of non-scaling sheet metal having a low thermal conduction characteristic, and intermediate support means, interposed bEtween said inner support element and surface layer, for supporting and thermally insulating said surface layer on said inner support element.
 6. The apparatus recited in claim 5, wherein said intermediate support means comprises thermal insulation material.
 7. The apparatus recited in claim 5, wherein said intermediate support means comprises a plurality of support members disposed on the surface of said inner support element.
 8. The apparatus recited in claim 7, wherein said support members comprise a plurality of interconnected circular wires disposed on the surface of said inner support element.
 9. The apparatus recited in claim 8, wherein said inner support element is conical in shape, and wherein said wires are disposed on the surface of said inner support element along the lines thereof of steepest gradient, and are interconnected so as to form a basket shaped intermediate support element.
 10. The apparatus recited in claim 3, wherein said extruding tool comprises an inner support element and a surface layer disposed thereon fabricated of non-scaling sheet metal having a low thermal conduction characteristic, said inner support element having a plurality of surface grooves disposed therein for forming a support surface for said surface layer which is diminished in area with respect to the total surface area of said inner support element.
 11. The apparatus recited in claim 10, wherein said inner support element is conical in shape and said grooves extend axially along the lines thereof of steepest gradient.
 12. The apparatus recited in claim 10, wherein said inner support element is conical in shape and said grooves extend circumferentially over the surface thereof.
 13. The apparatus recited in claim 3, wherein said extruding tool comprises an inner support element and an outer surface layer of ceramic material disposed thereon.
 14. The apparatus recited in claim 3, wherein said extruding tool includes an upper portion having a shape corresponding to that of said opening in said article, and a lower portion having a shape corresponding to that of the flange to be formed.
 15. The apparatus recited in claim 14, wherein said upper portion and said opening are elliptical in shape, and wherein said lower portion and flange are circular in shape.
 16. The apparatus recited in claim 15, wherein the surface shape of said extruding tool is in the form of a tractrix curve. 